Carburetors for internal combustion engines



July 17, 1956 J. c SLONNEGER CARBURETORS FOR INTERNAL COMBUSTION ENGINES Filed Nov. 3, 1952 2 Sheets-Shoot 1 INVENTOR John G. S/onneger ATTORNEYS United States Patent Ofi ce 2,755,074 Patented July 17, 1956 CARBURETORS FOR INTERNAL COMBUSTION ENGINES John C. Slonneger, Dallas, Tern, assignor, by mesne assignments, to The Youngstown Sheet and Tube Company, Youngstown, Ohio,-a corporation of Ohio Application November 3, 1952, Serial No. 318,443

3 Claims. (Cl. 261-16) This invention relates to new and useful improvements in carburetors for internal combustion engines.

The invention is particularly concerned with the carbureting or mixing of liquid and gaseous or other fuels, simultaneously, or independently, with air to provide a fuel mixture for use in internal combustion engines.

Although the invention is susceptible to use in many instances, it will be described primarily in conjunction with use upon pumping engines for oil wells since such use -is well known and wide spread and offers a simple and convenient example for description of the invention. The reference to oil well pumping engines is not to be construed as a limitation, but rather as a ready means for concise description of the inventive concept here involved.

in the past, many internal combustion engines have been operated upon gaseous fuels, such as natural gas obtained from oil wells, because the gas was readily available, was plentiful, and quite inexpensive when employed-at its source. It has also been the custom to operate such engines upon liquid fuels, such as gasoline, and further, to provide dual carburetion systems whereby an engine might be operated upon either liquid or gaseous fuels. In the latter case, the gaseous fuel is used so long as thesupply thereof is adequate, the engine being shifted to liquid fuel when the supply of fuel gas is insufficientto operate the engine. Such systems, however, have operated entirely on one fuel or the other, depending upon the state of supply and make no provision for employing such quantities of the gaseous fuel as may be available even though such supply may very nearly meet the requirements of the engine. Thus, even though the supply of fuel gas is only slightly less than the amount required to operate the engine, the operator is forced to abandon the natural gas supply entirely as a fuel and operate solely on purchased liquid fuel. The insufficient supply of natural gas must be allowed to escape or be burned in a flare and so becomes a total loss.

It is, therefore, the principal object of this invention to provide an improved carburetor for internal combustion engines which will employ whatever quantities of gaseous fuel as may be available for combustion in the engine, and which will automatically supplement such gaseous fuel with liquid fuel in the quantities and proportions as may be required to insure continuous operation of the engine.

An additional object of the invention is to provide an improved carburetor for internal combustion engines adapted to operate exclusively upon one fuel so long as such fuel is available in sufficient quantities, and to supply to the engine a second fuel in such metered quantitles and proportions as may be required when the available supply of the first fuel fallsbelow the minimum necessary to maintain normal and proper operation of the engine, the carburetor being adapted to increase and decrease the supply of the second fuel proportionally as the supply of the first fuel may decrease or increase, and

to supply the engine exclusively with the second fuel in the event the supply of the first fuel fails entirely.

An important object of the invention is to provide an improved carburetor for internal combustion engines which is adapted to supply a gaseous fuel or a liquid fuel, either independently or simultaneously, to the engine, the carburetor supplying gaseous fuel and at all times utilizing gaseous fuel exclusively if the same is available in adequate quantities; which at all times employs the entire supply of gaseous fuel if the same is inadequate, and which supplements the supply of gaseous fuel with liquid fuel only in such quantities necessary to bring the total fuel supply to the engine up to the desired or necessary level to the end that the use of liquid fuel is restricted to a minimum at all times.

A construction designed to carry out the invention will be hereinafter described together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, wherein an example of the invention is shown, and wherein:

Fig. 1 is a view in elevation showing in conjunction with fuel supply pipes and a conventional gas metering valve or structure, a carburetor assembly constructed in accordance with this invention,

Fig. 2 is an enlarged View in elevation of the carburetor, viewing the same from the intake manifold of the engine,

Fig. 3 is an end elevation of the carburetor taken from the left-hand end of Fig. 2,

Fig. 4 is a plan view of the carburetor,

Fig. 5 is an end elevation of the carburetor taken from the right-hand end of Fig. 2,

Fig. 6 is a horizontal, sectional view through the carburetor taken on the lines dof Fig. 2,

'Fig. 7 is a vertical, sectional view taken upon the lines 7-7 of Fig. 6, and

Fig. 8 is a fragmentary, horizontal, sectional view showing the structure of the liquid fuel inlet jet or tube.

in the drawings, the numeral 10 designates a carburetor constructed in accordance with this invention and supplied with gaseous fuel through a pipe 11 leading from a gas carburetor or gas metering valve 12 and a cut-oif valve 13. The metering valve 12 may be of any suitable or desirable construction and functions to regulate the fiow of gaseous fuel to the engine in proportion to the flow of air entering the engine. For example, the valve may be of the type shown in my Patent No. 2,599,872, issued June 10, 1952.

Gaseous fuel may be supplied to the valve 12 from the conventional low pressure tank (not shown) commonly termed a volume tank. Liquid fuel, such as gasoline, is supplied from a suitable storage tank (not shown) through the usual type of fuel pump (not shown) and enters the system by a liquid fuel supply pipe 14 and a suitable shut-off valve 15. As will be explained more fully hereinafter, a liquid fuel overflow pipe 16 may desirably be included in the system, and such pipe returns to the liquid fuel storage tank.

The carburetor forming the subject matter of this inventionincludes the usual air intake stack or conductor 1.7 through which combustion air flows to the intake manifold (shown in dotted lines at 1.8 in Fig. 6) of an internal combustion engine. The intake stack is provided with the conventional throttle valve 19, and the usual gaseous fuel inlet fitting 20 extends into the bore of the stack. The gas supply pipe 11 leads to and is connected with the fitting 20 for supplying gaseous fuel to the engine intake stack. The valve 13 is employed for admitting or shutting off the supply of gaseous fuel to the intake stack, and the metering valve 12 functions in a normal manner, sensing pressural conditions in the intake stack and metering gaseous fuel thereto in the proper quantities and proportions. With the exception of the liquid fuel supply, the structure thus far described is conventional in the art.

The improved carburetor includes a liquid fuel float housing or chamber 21 constructed for mounting in any suitable fashion on one side of the air intake stack 17. The member 21 includes a rectangular liquid fuel bowl 22 having the liquid fuel supply line connected thereinto through the valve 15 which communicates with the interior of the bowl 22 through the bottom thereof. The usual and conventional liquid fuel control valve 23 is disposed within the bowl 22 and regulates the flow of liquid fuel thereinto, the valve being actuated by the usual float 24 mounted upon an operating arm 25. The float and valve cooperate to maintain a supply of liquid fuel within the bowl 22 at a selected or predetermined level at all times. A cover plate 26 is provided for the open upper end of the bowl, and the liquid fuel overflow line 16 is connected into the upper portion of the liquid fuel housing thus formed in order to accommodate any excess supply of liquid fuel. It sometimes happens that float operated valves such as the valve 23, fail to close entirely, and in the event there is an oversupply of liquid fuel to the bowl 22, the excess is drawn off through the pipe 16 and returned to the liquid fuel storage tank.

On the opposite side of the air intake stack, and in substantial alinement with the liquid fuel supply housing 21, there is provided a regulator housing 27 having provision for suitable attachment to the air intake stack. The housing 27 is provided at one side with a cover plate 28 and carries on its other side one-half or one section 29 of a diaphragm housing. A dished or domed cover plate 30 is secured to the section 29 so as to constitute a diaphragm enclosure therebetween, and a suitable diaphragm or other flexible or pressure-responsive member 31 has its marginal edges clamped between the cover plate 30 and the section 29. The cover plate 30 carries an axially, outwardly extending sleeve 32 having an axial bore 33 extending therethrough. The diaphragm 31 has a plunger 34 extending therethrough, the plunger being secured to the diaphragm for movement therewith by means of the conventional washer 35 and nut 36. The portion of the plunger extending outwardly from the diaphragm is of relatively small diameter and extends through the bore 33 of the sleeve 32 to a point adjacent the outer end of said sleeve. The inner portion of the bore 33 is enlarged to form a counter-bore 37 and a shoulder 38, while a compression spring 39 encircles the outer portion of the plunger and is confined between the shoulder 38 and the nut 36. Thus, the spring 39 functions to urge the diaphragm constantly away from the sleeve 32 and toward the housing 27. A screw-threaded adjusting bolt 40 is positioned in the outer end of the bore 33 and carries a conventional lock nut 41. The inner end of the screw 40 is spaced from the outer end of the plunger 34, but it is apparent that the screw 40 may be adjusted to limit the outward travel of the plunger and hence the movement of the diaphragm 31 away from the housing 27.

The opposite end of the plunger 34 extends through the bottom of the section 29 into the interior of the housing 27 through an over-sized opening 42 and engages one arm 43 of a bell crank lever pivotally mounted within the housing 27 upon a transverse bolt or other support 44. The opposite arm 45 of the bell crank lever is provided with a boss 46 which faces toward the air intake stack. The compression spring 39 thus constantly urges the bell crank lever to swing so as to move the boss 46 toward the air intake stack.

For supplying liquid fuel to the intake stack, the latter is provided with a liquid fuel jetting tube 47 extending transversely of the stack between the housings 21 and 27. The float chamber end of the tube 47 is flanged to form a head 48 which is received within a complementary recess 49 provided in the float chamber housing, and the head is provided with a radial groove 50 which receives a key 51 formed in the recess 49. The groove and key arrangement insures the proper rotational positioning of the tube 47 within the intake stack.

The opposite end of the tube is screw-threaded and receives a nut 52 which engages the outer wall of the intake stack and securely clamps the tube 47 in position. The wall of the housing 27 which abuts the stack 17 is cut away at 53 to accommodate the nut 52.

The tube 47 is provided with an axial bore 54 extending throughout its length and being reduced in diameter adjacent the float chamber end of the tube to form a metering valve seat 55. The bore receives a metering valve needle 56 having a knurled head 57 and extending into the bore from the housing 27. The medial portion of the needle is reduced in diameter to form a flow space 58 between the needle and the wall of the bore 54, while the extremity of the needle is tapered to form the conventional needle valve 59 adapted to engage the valve seat 55. A compression spring 60 is confined between the head 57 and the nut 52 and constantly urges the valve needle away from the seat 55.

As shown in Fig. 6, the tube 47 and its needle valve plunger 56 are alined with the boss 46 and extend across the air intake stack upstream of the throttle valve 19. The float chamber housing 21 is provided with a liquid fuel passage 6]. extending from below the liquid fuel level in the chamber to the recess 49 and the bore 54 of the tube 47, and hence, when the needle valve 59 is unseated, liquid fuel may flow from the float chamber into the bore 54 and the space 58 around the plunger 56. In order to admit the liquid fuel to the bore of the air intake stack, the tube 47 is provided with a plurality of openings 62 which face downstream in the air intake stack toward the throttle valve 19. This positioning of the openings 62 permits the flow of air through the intake stack to exert a suction effect thereon whereby fuel is withdrawn from the float chamber 21 and directed into the air intake stack. Manifestly, the number, positioning, and area of the openings 62 are suitably selected in order to provide a proper carbureting action and the desired mixing of the liquid fuel with the air stream t form a combustion mixture.

It will be seen that the spring 60 biases the needle valve 59 toward an opened position, whereas the spring 39, acting through the plunger 34, the arm 43 of the bell crank lever and the boss'46 on the arm 45 of said lever, biases the valve toward a closed position. In addition, the space between the diaphragm 31 and the cover plate 30 is placed in communication with the source of supply of the gaseous fuel by means of an inlet pipe 63 leading to the interior of said space through an inlet connection 64 formed in the cover plate 30. The opposite side of the diaphragm is exposed to atmospheric pressure through a vent opening 65 in the section 29, and it follows that the diaphragm is biased toward a needle valve closing position when there is available at the source of supply of gaseous fuel a pressure above atmospheric.

This latter biasing force is adjustably offset to some degree by a tension spring 66 which urges the bell crank lever to move to permit opening of the needle valve. The arm 45 of the lever carries a plurality of closely spaced notches 67 which receive one end of the spring 66, and the opposite end of the spring is secured to the inner end of a screw-threaded bolt 68 extending through the side wall of the housing 27. The bolt carries an adjusting nut 69 by means of which the tension exerted by the spring 66 may be regulated.

In order that the carburetor may operate properly on both types of fuel, it is desirably adjusted after installation by first shutting off the liquid fuel supply, as by closure of the valve 15. The gas metering valve 12 is then adjusted in the usual manner to provide for proper operation of the engine when the latter is running exclusively on a supply of gaseous fuel. Following this operation, the gas supply may be cut off by closing of the valve 13, the liquid fuel supply readmitted by opening of the valve 15 and the screw-threaded bolt 40 adjusted to limit the travel of the plunger 34 and hence the opening of the needle valve 59. The latter adjustment is made to achieve proper operation when the engine is running exclusively on the liquid fuel supply, and an initial adjustment of the apparatus is thus achieved.

It is to be noted that the opening of the needle valve 59 is affected by the forces exerted by the springs 39 and 6t and by the atmospheric pressure exerted upon one side of the diaphragm 31. All of these factors are fixed, and the value of the springs 39 and 60 may be selected in order to place the sensitivity of the apparatus within the desired range.

The opening of the needle valve is also affected by the pressure exerted from the gaseous fuel supply upon the other side of the diaphragm, this pressure being variable, and by the force exerted by the springs 66, the latter force also being variable by adjustment of the bolt 68 and by positioning of the spring 66 in various ones of the notches 67. During operation of the device upon gaseous fuel, the pressure exerted through the inlet pipe 63 upon the diaphragm 31 coupled with force exerted by the spring 39 is adequate to overcome atmospheric pressure exerted upon the opposite side of the diaphragm, and the forces exerted by the springs 60 and 66. Hence, the needle valve remains closed and the carburetor supplies gaseous fuel exclusively to the engine. As the pressure of the fuel gas declines, a point will be reached at which the supply of fuel is inadequate and must be supplemented by liquid fuel. The bolt 68, which is freely slidable in the wall of the housing 27 and is maintained in position by the adjustment of the nut 69, is therefore adjusted to cause the needle valve to commence opening when this critical point is reached at which supplementary fuel is desired. Of course, as the pressure of the fuel gas declines further or drops to atmospheric pressure the needle valve opens progressively further so as to maintain an adequate supply of fuel to the engine. Should the pressure of the fuel gas increase, the increased pressure upon the diaphragm 31 causes the needle valve to move toward a closed position, and hence, the device constantly regulates the ratio of gaseous fuel and liquid fuel supplied to the engine in order to utilize as fully as possible gaseous fuel and to supplement such supply with liquid fuel when such is required.

The provision of the notches 67 in the arm 45 of the bell crank lever is primarily for the purpose of accommodating various qualities or types of fuel gas. Natural gases vary considerably from well to well, and other types of fuel gas vary to a marked extent, particularly as to calorific content and eflicacy as a fuel gas. Consequently, a supply of a comparatively rich gas under a relatively low pressure may be adequate to operate the engine whereas a lean gas Would necessarily have to be under a considerably higher pressure in order that adequate quantities thereof might be supplied to the engine. Therefore, for rich gases, the spring 66 will be positioned in one of the notches 67 adjacent the boss 46 and the pivot point 44 of the bell crank lever. For leaner gases, however, the spring 66 would be positioned in one of the notches 67 nearer the outer end of the arm 45 so that a gas supply of higher pressure would be required in order to hold the needle valve 59 closed. Of course, regardless of which of the notches receives the spring 66, the spring is additionally adjustable by means of the nut 69 in order to regulate the fuel air ratio of the combustion mixture going to the engine at such times when a mixture of liquid and gaseous fuels is being employed.

It is to be understood that the gaseous fuel metering valve 12 may be of any suitable or acceptable type or design capable of supplying gaseous fuel in proper quantities and proportions for the satisfactory operation of the engine on gaseous fuel only. Likewise, the liquid fuel carburetor represented by the float chamber 21 and the metering tube 47 may be of any convenient or suitable design. The invention is readily adaptable to carburetors using more than one jet by suitable modification to control more than one of the needle valves, either directly or by suitable linkage, and such is within the scope of this invention. The disposition of the elements of this system, as shown in the drawings, have been chosen for clarity of exposition, so that alteration or other arrangement of the elements is permissible so long as the practical functioning of the system is not impaired.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

l. A carburetor for simultaneously supplying fuel from two sources to an internal combustion engine including; an engine air intake stack having an inlet and a fuel mixture outlet to the engine; a conductor for supplying fuel from one source to the engine air intake stack; a variable metering valve in said conductor; a second conductor for supplying fuel under pressure from a second source to the engine air intake stack; pressure-responsive means in communication with the second source of fuel; a motiontransmitting connection between the pressure-responsive means and the metering valve; the pressure-responsive means being responsive to pressure exerted from the second source to bias the metering valve through the motion-transmitting connection toward a closed position; the motion-transmitting connection including, a variable spring permitting the metering valve to move toward an open position, and a bell crank lever having one arm receiving a thrust from the pressure-responsive means and the other arm exerting a thrust on the metering valve; the spring engaging one arm, and means for shifting the point of engagement of the spring along the length of said arm.

2. A carburetor for preferentially supplying a gaseous fuel from a source of such fuel under pressure into an air stream to an internal combustion engine and for supplementing the supply of gaseous fuel with a supply of liquid fuel when the supply of gaseous fuel decreases, including, an air intake stack for the engine, a liquid fuel float chamber carried on the stack, a motion-transmitting means carried on the stack, a liquid fuel conductor leading from the float chamber into the stack and discharging into the air stream, a valve seat interposed in the con ductor, a metering valve adapted to engage the seat and having a stern extending from the conductor to the motiontransmitting means, distributing means connected with the valve and located in the stack for discharging liquid fuel into the path of the air stream, a diaphragm carried by the stack and engaging the motion-transmitting means, a second conductor for supplying gaseous fuel to the stack from a source of gaseous fuel under pressure, and means for placing one side of the diaphragm in communication with said source of gaseous fuel, whereby the proportions of gaseous fuel and liquid fuel may be varied without altering the volume of air flowing through the stack.

3. A carburetor as set forth in claim 1 wherein movement of the diaphragm in one direction causes biasing of the valve away from the seat and movement of the diaphragm in the other direction causes biasing of the valve toward the seat, and means for adjustably limiting movement of the valve away from the seat.

References Cited in the file of this patent UNITED STATES PATENTS 1,891,238 Oswald Dec. 20, 1932 2,326,205 Dowdell Aug. 10, 1943 2,409,611 Bodine Oct. 22, 1946 2,541,316 Winkler Feb. 13, 1951 2,592,304 Lubelay Apr. 8, 1952 

